// Simple command-line kernel monitor useful for
// controlling the kernel and exploring the system interactively.

#include <inc/stdio.h>
#include <inc/string.h>
#include <inc/memlayout.h>
#include <inc/assert.h>
#include <inc/x86.h>

#include <kern/console.h>
#include <kern/monitor.h>
#include <kern/kdebug.h>

#define CMDBUF_SIZE	80	// enough for one VGA text line


struct Command {
	const char *name;
	const char *desc;
	// return -1 to force monitor to exit
	int (*func)(int argc, char** argv, struct Trapframe* tf);
};

static struct Command commands[] = {
	{ "help", "Display this list of commands", mon_help },
	{ "kerninfo", "Display information about the kernel", mon_kerninfo },
	{ "backtrace", "backtrace the stack", mon_backtrace },
};
#define NCOMMANDS (sizeof(commands)/sizeof(commands[0]))

unsigned read_eip();

/***** Implementations of basic kernel monitor commands *****/

int
mon_help(int argc, char **argv, struct Trapframe *tf)
{
	int i;

	for (i = 0; i < NCOMMANDS; i++)
		cprintf("%s - %s\n", commands[i].name, commands[i].desc);
	return 0;
}

int
mon_kerninfo(int argc, char **argv, struct Trapframe *tf)
{
	extern char _start[], etext[], edata[], end[];

	cprintf("Special kernel symbols:\n");
	cprintf("  _start %08x (virt)  %08x (phys)\n", _start, _start - KERNBASE);
	cprintf("  etext  %08x (virt)  %08x (phys)\n", etext, etext - KERNBASE);
	cprintf("  edata  %08x (virt)  %08x (phys)\n", edata, edata - KERNBASE);
	cprintf("  end    %08x (virt)  %08x (phys)\n", end, end - KERNBASE);
	cprintf("Kernel executable memory footprint: %dKB\n",
		(end-_start+1023)/1024);
	return 0;
}

int
mon_backtrace(int argc, char **argv, struct Trapframe *tf)
{
	// Your code here.
        // Sample:
        // Stack backtrace:
        // ebp f0109e58  eip f0100a62  args 00000001 f0109e80 f0109e98 f0100ed2 00000031
        // ...

        physaddr_t ebp = read_ebp();
        physaddr_t eip = read_eip();
        
        while(ebp != 0)
        {
          physaddr_t* pEbp = (physaddr_t*)ebp;
          //cprintf("!!!! ebpAddr:%08x  pEbp(physaddr_t*)ebpAddr:%08x pEbp+1:%08x\n",ebp,pEbp,pEbp+1);
          physaddr_t arg1 = *(pEbp+2);
          physaddr_t arg2 = *(pEbp+3);
          physaddr_t arg3 = *(pEbp+4);
          physaddr_t arg4 = *(pEbp+5);
          physaddr_t arg5 = *(pEbp+6);

          // get debug info
          struct Eipdebuginfo info;
          debuginfo_eip(eip,&info);
          const char* filename = info.eip_file;
          int linenum = info.eip_line;

          // not null terminated, add '\0' to end of function name 
          int fn_namelen = info.eip_fn_namelen;
          char funcname[fn_namelen+1];
          strncpy(funcname,info.eip_fn_name,fn_namelen);
          funcname[fn_namelen] = '\0';

          cprintf("%s:%d: %s\n  ebp %08x eip %08x args %08x %08x %08x %08x %08x\n",
              filename,linenum,funcname,ebp,eip,arg1,arg2,arg3,arg4,arg5);
          ebp = *pEbp;
          eip = *(pEbp+1);
        }
        return 0;
}



/***** Kernel monitor command interpreter *****/

#define WHITESPACE "\t\r\n "
#define MAXARGS 16

static int
runcmd(char *buf, struct Trapframe *tf)
{
	int argc;
	char *argv[MAXARGS];
	int i;

	// Parse the command buffer into whitespace-separated arguments
	argc = 0;
	argv[argc] = 0;
	while (1) {
		// gobble whitespace
		while (*buf && strchr(WHITESPACE, *buf))
			*buf++ = 0;
		if (*buf == 0)
			break;

		// save and scan past next arg
		if (argc == MAXARGS-1) {
			cprintf("Too many arguments (max %d)\n", MAXARGS);
			return 0;
		}
		argv[argc++] = buf;
		while (*buf && !strchr(WHITESPACE, *buf))
			buf++;
	}
	argv[argc] = 0;

	// Lookup and invoke the command
	if (argc == 0)
		return 0;
	for (i = 0; i < NCOMMANDS; i++) {
		if (strcmp(argv[0], commands[i].name) == 0)
			return commands[i].func(argc, argv, tf);
	}
	cprintf("Unknown command '%s'\n", argv[0]);
	return 0;
}

void
monitor(struct Trapframe *tf)
{
	char *buf;

	cprintf("Welcome to the JOS kernel monitor!\n");
	cprintf("Type 'help' for a list of commands.\n");


	while (1) {
		buf = readline("K> ");
		if (buf != NULL)
			if (runcmd(buf, tf) < 0)
				break;
	}
}

// return EIP of caller.
// does not work if inlined.
// putting at the end of the file seems to prevent inlining.
unsigned
read_eip()
{
	uint32_t callerpc;
	__asm __volatile("movl 4(%%ebp), %0" : "=r" (callerpc));
	return callerpc;
}
